Flexible elongated member tensioning device



p 1953 H. c. UHLIG FLEXIBLE ELONGATED MEMBER TENSIONING DEVICE Filed Aug. 25, 1948 2 Sheets-Sheet l Zinnentor HEIWPYC UHLIG ax/um Patented Sept. 1, 1953 UNITED STATE PATENT OFFICE 2,650,779 ELONGATEDMEMBER; TENSIONING DEVICE Henry C. Uhlig,v Clifton, N. J assignor, by mesne assignments, to Howe Twister Corporation, Jersey City, Ni .L, a corporation of New Jersey Application August 25, 1948, Serial No. 46,108

7 Claims. 1

This invention relates to an improved, simplifiedtensioning device for flexibleelongated mem bers suchas yarns, threads; and the like; the tensioning device being adaptedto impose a predetermined tension upon the flexible elongated member as the latter travels therethrcugha- The invention has among its objects the provision of a tensionin-g device of the character indicated of simple, rugged construction, device being economicalto make and easy to maintain.

The invention has as a'further object the provision of a tension device of such construction that high tensions may be imposed upon an elem-- gated flexible member traveling therethrougl-r without injury to such member.

Yet another object of the invention resides in the provision of a tension device of the character and for the purpose indicated which the amount of tension imposed upon the elongated flexible member may be easily and quickly varied as desired.

These and further objects or the invention will be more readily apparent the fol-lowing description of preferred embodiments of the tem sioning device of the invention.

Many operations upon elongated flexible members such as yarns; threads, fine wires and like requirethat a predetermined back tension shall be imposed upon such members during travel thereof, Typical of such operations are the winding: of such flexible elongated members;- the twisting of yarns to" form threads; and the combining or doubling of threads to form cords; Requisites of a successful tensi'oningdevice for suchoperations are the maintenance of a sub stantiallyconstant predetermined tensiorr upon the member, the abili-ty of the. tensioning device to impose a-high tension on the memberwitho'u t substantial injury thereto, and adjustability whereby the amount of tension imposed may be:

varied within appreciable limitst l he tensioning device of the present invention is particularly" characterized by possessing" all-three o'f the above: requirements, plus simplicity and freedom from:

substantial wear ofthe tensionimp'osingparts over long periods of operation.

The tensionin'g' device of the invention is illus-- trated and described herein primarily in connec-- tion with the twisting of a flat yarn; made up" of aplurality ofcontinuoussynthetic fibers; to

form a thread. It is tobe understood; however; and it has been indicated above; that the hem sioning device is capable of use to advantage connection with other operations on elongated 2 flexible members. It'- is also to be understood that the elongated flexible members may be yarns made upof' either natural or synthetic fibers;-

Fig. 2 is an enlarged view in axialsection through the top portion of the tensionin g device of the invention shown in Fig 1';

Fig. 3 is a view in section transverse to the axis of the spindlethrough the magnetsystem of the tensioning device, the section being taken along the line 3-3 in both Figures 1 and 2;

Fig. 4 is an enlarged view in axial section through the topportion of a tensioning device made in accordance with a second preferred em bodiment or the invention;

Fig.5 is-a view'in' plan of the tensioning' device shown in- Fig. 4;

Fig. 6 is-a view in axial section similar to Figs 2 and 4'- of a third embodiment of the tensioning device.

The tensio'nin device of the invention, partic-' ularlythose embodiments shownin Figs. 1-6', inelusive, have proved to be especiallyuseful twisting spindles although; of course, they are capable of manyother uses. For purposesof illustrationthe tensi'cnin'gdevice is shown in Fig.-

1" as being incorporated in a two-for-one twisting spindle suchas that shown in Fig. 5' oi my prior application for United States Letters Patent,

Serial No. 765*,57 '7 filed August 1,-1947 Thetensioning device of the prese'ntinvention is shown in Fig.- 1'- ofthepresenti disclosure as substituted for the tensioning device 100 shown in- Figs: 7-1 1 inclusive; ofmy prior above referred to.

The two-for-one twisting spindle generally designatedd. shown mag; 1 operates inthisinspecifically application stance-uponflat yarnsupplied from a bobbin or package, the yarnbeing given two twists for eachrevolution of the spindle asthe yarntravels therethrough. By" the term flat-yarn there is meant a--yarn= in theform of a tapeo'f'ge'nerally rectangular cross section thewidth of the tape materially exceeding its thickness: Such flat yarn form is that which extruded synthetic fibers are usually gathered into a package. The spindle shown in Fig. 1 is supported on a machine frame, a portion of which is shown at 8, through the medium of a sleeve l mounted on the frame, the sleeve carrying at its upper and lower ends, respectively, the ball bearing l2 and I4. Journaled in such ball bearings is the generally upright driven shaft 6, to which is keyed the pulley [6 from which the shaft is rotated by a driving belt (not shown). Keyed to shaft 6 above the pulley is a disc l8. Above such disc, and floatingly mounted on the upper end of shaft 6, is a bobbin holder, generally designated by the reference character 20. Such bobbin holder has a lower flange portion 22 and a central sleeve portion 24, the latter surrounding and being spaced from the upper end of shaft 6. The ball bearing 26 at the upper end of sleeve 24 and the ball bearing 28 at the lower end of the bobbin support mount such support floatingly on the driven shaft 6, so that the bobbin support may remain essentially non-rotative. The bobbin support is maintained in essentially fixed angular position by means of the weight 30 mounted beneath flange 22 at one zone thereof, the spindle in use being mounted with its axis at a small angle, such as 12, to the vertical, as disclosed in my said prior application.

The yarn to be twisted is contained in the wound package 32 which is provided with a core 34. The lower end of such core rests upon the upper surface of flange 22, the package being held centrally of the spindle by means of the lower and upper annular spacers 38 and 45, respectively. A thin-walled tube 36, which surrounds sleeve 24, serves to retain the outer race of bearing 26 and also serves as a support for the tensioning device now to be described. 1

Such tensioning device, which is generally desnated by the reference character 2, has a main body 42 which is generally of circular cylindrical shape. The lower end 46 of the body is of slightly less diameter than the upper portion thereof so that the former fits within the upper end of tube 36, shoulder 44 on the body 42 resting on top or the tube. The yarn 48 delivered from package 32 runs upwardly, as shown, to the upper end of the tensioning device, thence downwardly therethrough, into and through the twisting and guiding means 50 mounted on the top of shaft 6 so as to rotate therewith, thence downwardly through the axial passage 52 in the upper end of shaft 6 and outwardly through the radial passage 56, passages 52 and 56 being connected by the curved passage 54 in shaft 6. The product emerges from the outer end of passage 56 as the doubletwisted thread 49, thread 49 passing upwardly to a stationary guiding eye (not shown) positioned above and substantially coaxial with the upper end of the spindle. In that portion of its travel denoted 58 the yarn receives a first twist, by reason of the relative rotation of means 2 and 50. In the subsequent portion of its travel through the spindle, indicated at 60, the first twisted yarn receives a further twist by reason of the rotation of disc Ill.

The structure of the upper active end of the tension device shown in Fig. l is more clearly shown in Fig. 2. Body 42, which is made of nonmagnetic material such as aluminum, is provided at its upper end with an axial counterbore 65 the bottom of which communicates with the central axial bore 68 through body 42, as shown in Fig. 1. Positioned in the counterbore 65 and resting on the bottom thereof are two similarly 4 shaped U-shaped permanent magnets, In and 12, the magnets being positioned so that their unlike poles confront each other. Thus poles l3 and '14 of magnet 10 are north and south poles, respectively, and poles 15 and 16 of magnet 12 are south and north poles, respectively. It is preferred that magnets 10 and 12 be retained in fixed position in the counterbore relative to each other by means of thin spacer or shim members 18 of non-magnetic material such as hard rubber, brass or the like, which are interposed between the confronting poles of the magnets, although the magnets tend to stay in the positions shown withoutsuch spacers, owing to the balanced attractions between the sets of confronting poles. Magnets 10 and 2 are preferably made to have at least generally the same size and magnetic field strength, and are preferably made of material having high permeability. The magnetic alloy composed of 24-30% Ni, 9-13% Al, balance Fe, and the alloy composed of 24-30% Ni, 943% A1, 540% C0, balance Fe, are typical of the known alloys which may be employed for the magnets. Positioned in the bore 66 above the magnets is the annular seat providing member made of a non-magnetic material which is preferably hard and wear resistant. In the described embodiment member 80 is made of stainless steel of the well-known 18% Cr, 8% Ni type. Member 80 is provided on its upper surface with a centrally located, accurately finished and highly polished continuous annular seat 82, the surface of which lies on an imaginary sphere. Below the seat, member 80 is provided with an elongated flexible member receiving central axial bore 84, the juncture between the seat 82 and bore 84 constituting a constricted neck in the former. The spacing between seat providing member 89 and magnets 10 and 12 is determined by the annular shims 86 which separate the magnets from member 80. In this instance two such shims are shown. Member 80 is held against escape from the counterbore by means of the spring ring 88 of non-magnetic material, such as Phosphor bronze, which snaps into an annular recess in the upper end of the counterbore. A highly polished carbon steel ball 90, which is thus magnetic, rests in the seat 82 in member 80, the ball having a diameter greater than the largest transverse dimension of the seat, the ball being retained in the seat both by gravity and by attraction from the magnet system composed of magnets 10 and "I2. At least part of the flux from the confronting poles of the opposite magnets passes upwardly through the steel ball 90 and thence downwardly to the confronting pole of the other magnet of the pair so that the ball is included in the magnetic circuit. In Figs. 1 and 2 the ball 90 has a diameter equal to that of the imaginary sphere on which seat 82 lies.

The pole strengths of the magnets remain substantially constant and thus the force with which the ball is attracted toward the magnets is substantially solely a function of its distance from the magnets. Thus by varying the distance from the ball to the magnets, as by changing the total thickness of the spacer members 86, the force with which ball 90 presses upon seat 82 may be varied. It is to be understood that although gravity assists in retaining the ball in the seat when the tensioning device is positioned as shown, the attraction of the ball by the magnet system far surpasses the effect of gravity and that the tensioning device may be employed oi the magnetic field upon in any desired angular position, even upside down.

As is apparent in Figs. 1, 2, 4, 5, and 6 of the drawing, which show species of the invention employing a magnetic ball as the second tensioning member, in each case the ball has a diameter which is markedly less than the diameter of the counterbore 66 and thus of the magnet system composed of the two U-shaped magnets and 1:2. As is also apparent in these figures, the ball has a diameter which is of the same order of magnitude as the axial bore through the interiors of the magnet pieces 70 and E2, the diameter of the ball as shown in Figs. 1, 2, 4, and 5 somewhat exceeding the diameter of such bore through the magnets, whereas the ball shown in Fig. 6 has a diameter somewhat less than such bore through the magnets. As a result of such relationship between the diameter of the ball and the outer diameter of the magnet system, the relationship between the diameter of the ball and the central axial bore through the magnet system, as well as the facts that the ball is symmetrically placed relative to the magnet system so as to lie coaxial of the bore therethrough and is located relatively close to the magnet system, not onlyis the ball held stably in th seat by the action of gravity and also by the action of the magnetic field in pulling it into the seat, but it is also strongly impelled into a central position coaxial of the magnet system by the magnetic field actingupon it. Thus the ball is stably held in the seat in the second tensioning member by three forces: (1) gravity, (2) the action of the magnetic field in a downward direction, supplementing gravity, and (3) the action the ball which always tends to return the ball to a position in which it lies coaxial of themagnet system.

The tensioningdevice i provided with an axial guiding tube 94' ofnon-magnetic material such as brass, tube 94 being retained by having its lower end telescoped into a counterborells at the upper end of the bore 68, as shown in Fig. 1. Theupper end of tube 94' is flared at 98 so that its outer edge lies substantially under member 88, to provide a smooth passage for the yarn therethrough.

The yarn 68 is shown entering the tensioning device by traveling upwardly over the smoothly rounded upper edge 92- of body 42 and thence downwardly between ball 90 and seat 82. There is thus imposed on yarn 48 a retarding friction as it slides past the seat, such retarding friction being a direct function of the force with which the ball thrust the yarn against the-seat. Because the yarn is flat, it tends to lie with its broad surfaces in contact with the seat and the ball, which thus in addition to tensioning the yarn, prevent rotation of the yarn about its axis.

The tensioning device thus far described, which employs a ball as one tensioning member, is'particul'arly advantageous for use indevices wherein the yarn is presented tothe tensioning device in a path which continually varies angularly with respect thereto. Thus in the two-forone twisting spindle shown, the yarn, by reason of its being unwrapped fromthe package in which-it is wound, continually travels around the axis of the-tensioning device as it is fed thereinto. The ball and its seat in the tensioning device-shownin Figs. 1, 2, and 3, are Wholly symmetrical about the longitudinal axis of the tensioning device, and thus such shifting of the from the packageby substituting for the path of feed of the yarn thereinto does not cause any variation in tension. The device thus far described is also advantageous since the yarn undergoes no sharp bends in its travel therethrough and is subjected to purely rolling friction on one side thereof. Thus high tension may be imposed on the yarn without injury thereto.

When the tensioning devices above described is employed so that the yarn feeds thereinto in a continually changing path it is further advantageous since the yarn continually contacts different portions of the seat and ball of the device. Thus the wear upon the seat and ball is evenly distributed thereover and the device may be used for long periods without requiring reshaping or redressing of either the seat or ball.

Where infinite variation of the strength, throughout the permissible range of adjustment of that portion of the field of the magnet system which acts upon the tensioning ball is desired, it is preferred to use the structure of the tensioning device shown in Figures 4 and 5. In such embodiment the tensioning device, generally designated IEII, has a main body portion I02 made of non-magnetic material such as aluminum, provided with an axial bore I 28 therethrough and a counterbore I94 coaxial therewith at the upper end of the body. Positioned at the bottom of the counterbore are two U-shaped magnets positioned in the same manner as the magnets IE! and E2 in the first described embodiment. In Figure 4 one such magnet I08 is shown, such magnet having the poles Hi9 and H6.

Positioned at the outer end of the counterbore I'M, with its bottom surface spaced from the upper surface of the magnets, is the seat providing member II2', made of non-magnetic material, member H2 having threaded engagement between its peripheral surface and the inner surface of the counterbore at I96. Member H2 is provided centrally thereof with a continuous annular seat H4 in the shape of a part of a sphere, and with a central aperture H5. The yarn engaging magnetic ball IIB, the surface of which substantially coincides with the surface of the seat H4; is held therein by gravity and the attraction of the magnet system in the same manner as in the first embodiment. Continuous. adjustment of the distance of the seat from the magnet system is permitted by the threaded mounting of member H2 in the. body I02, member I I2 conveniently being provided with spanner receiving openings I24 on its upper surface. When member II2' has thus been adjusted so that ball H8 is held in the seat with a predetermined desired force, it may be locked in such position by means of the locking mean consisting of the slot I23. cut into one edge of member H2, in the manner shown inFigures 4 and 5, and. the cap screw I22 which may be tightened to. cause the portions of the thread on member IIZ separated by the slot 22! to approach each other and thus lockingly engage the threads on the wall of the counterbore. The tensioning device of this embodiment is similarly provided with an internal guiding tube for receiving the yarn as it travels from the seat and'ball, the tube in this instance being designated I26.

In some instances it may be desired to alter the effective tension upon the yarn without taking the time to adjust the distance of the seat carrying member from the magnet system. This may readily be done, in tensioning devices such as those two embodiments-above described,

magnetic ball which substantially fits the seat a ball whose diameter is either substantially greater than or less than the diameter of the imaginary sphere on which the seat lies.

In Figure 6 there is shown a tensioning device in which the main body thereof and the parts attached thereto are substantially the same as those shown in Figures 4 and 5; such parts are accordingly designated by the same reference characters as those used in Figures 4 and 5 but with an added prime. The magnetic ball I30 employed in Figure 6, however, has a diameter substantially less than that of the imaginary sphere of which the seat H4 is a part and thus contact between the ball and seat is along substantially a circular line, or at most a narrow axially curved annulus, adjacent the bottom, constricted neck of the seat. Although the mass of the smaller ball is less than that of the larger ball, its center of mass lies closer to the magnet system and thus it is pulled into the seat with greater force by such magnet system than is the larger ball I 18 in Figs. 4 and 5. Thus, in general, the use of such smaller ball will impose a greater tension upon the yarn in spite of the fact that the frictional areas of the ball and seat engaged by the yarn are smaller than they are when the larger ball is used. By suitable simple tests an empirical table may be made up for any given tensioning device, so that, all other conditions being constant, the tension may be read as a function of the ball diameter.

Although I have described and illustrated preferred embodiments of the tensioning device of the invention, it is to embodiments are illustrative only since the device is capable of considerable variation as to details. The scope of the invention is therefore defined by the appended claims.

I claim as new the following:

1. A tensioning device for yarn or the like which comprises an elongated cylindrical main body made of non-magnetic material, the main body having an axial passage longitudinally therethrough, the main body having an axial counterbore at one end thereof, a first tensioning member in the form of a disc made of nonmagnetic material positioned in the outer end of the counterbore coaxial thereof, means for adjustably positioning the disc axially of the counterbore, said last named means comprising screw threads on the counterbore side walls and screw threads on the periphery of the disc engaged therewith, the disc having an axial opening therethrough, the disc having a seat in the shape of a portion of a sphere centrally thereof on its outer face, said seat communicating with the opening through the disc, said seat in the disc constituting a yarn engaging surface past which the yarn travels, a second tensioning member in the form of a ball rotatably supported in the seat, the ball having a diameter approxi mately equal to the diameter of the imaginary sphere of which the seat in the disc is a part, the ball being movable into and away from the seat in the first member, the yarn being compressed between the yarn engaging surfaces on the first and second members, the ball rotating in the seat with its periphery traveling in the direction of travel of the yarn, at least a portion of the ball symmetrically spaced about its center being made of magnetic material, a permanent magnet system positioned in the counterbore in the main body inwardly of the disc so that such system pulls the ball into the be understood that such 1 seat in the disc, said magnet system comprising a hollow cylindrical body located in the counterbore, the central opening through the hollow cylindrical body being coaxial of the counterbore, the hollow cylindrical body including at least two opposite magnetic poles positioned closely adjacent the aperture in the disc, the ball having a diameter which is substantially less than the outer diameter of the hollow cylindrical body, the ball having a diameter which is on the same order of magnitude as the diameter of the central opening through the hollow cylindrical body.

2. In a spindle having means to hold a hollow wound package of elongated flexible material such as yarn for delivery of the material therefrom by withdrawal of the material in a direction generally axial of the package, and means to guide the thus delivered material through the opening within the package: a tensioning device positioned generally within the opening in the package and receiving the material directly from the package along a path which continually rotates about the axis of the package and the tensioning device, said tensioning device comprising an elongated cylindrical main body made of non-magnetic material, the main body having an axial passage longitudinally therethrough, the main body having an axial counterbore at one end thereof, a first tensioning member in the form of a disc made of non-magnetic material positioned in the outer end of the counterbore axial thereof, means for adjustably positioning the disc axially of the counterbore, said last named means comprising screw threads on the counterbore side walls and screw threads on the periphery of the disc engaged therewith, the disc having an axial opening therethrough, the disc having a seat in the shape of a portion of a sphere centrally thereof on its outer face, said seat communicating with the opening through the disc, said seat in the disc constituting a yarn engaging surface past which the yarn travels, a second tensioning member in the form of a ball rotatably supported in the seat, the ball having a diameter approximately equal to the diameter of the imaginary sphere of which the seat in the disc is a part, the ball being movable into and away from the seat in the first member, the yarn being compressed between the yarn engaging surfaces on the first and second members, the ball rotating in the seat with its periphery traveling in the direction of travel of the yarn, at least a portion of the ball symmetrically spaced about its center being made of magnetic material, a permanent magnet system fixedly positioned in the counterbore in the main body inwardly of the disc so that such system pulls the ball into the seat in the disc, said magnet system comprising two similar U-shaped permanent magnets located in the counterbore with their unlike poles confronting and parallel to each other, the central opening through the thus placed magnets being coaxial of the counterbore, the thus placed magnets including at least two opposite magnetic poles positioned closely adjacent the aperture in the disc, the ball having a diameter which is substantially less than the outer diameter of the thus placed magnets, the ball having a diameter which is on the same order of magnitude as the diameter of the central opening through the thus placed magnets.

3. A tensioning device for yarn or other flexible strand material, comprising a seat element 9 cf non-magnetic material having a laterally extended upper surface formed centrally with an opening for free downward passage of a strand to be tensioned, a sphere of magnetic material to overlie said opening and bear upon said surface in tensioning relation to such strand, said sphere being rollable laterally on said surface to give any needed clearance for strand movement between the sphere and said opening, and magnet means below said seat element exerting through it a magnetic flux drawing the sphere to said surface with a predetermined force and urging the sphere from displaced positions on laterally extended parts of said surface to a centralized position over said opening.

4. A tensioning device for yarn or other flexible strand material, comprising a disc of nonmagnetic material having an axial bore therein for free passage of a strand to be tensioned and an upper surface symmetrically surrounding said bore including a concave recessed portion at said bore and a substantially flat outer portion around the recessed portion, a sphere of magnetic material lying on said recessed portion and over said bore to tension such strand, the sphere being upwardly unconfined and rollable laterally on said surface to give any needed clearance for strand movement between itself and said bore, its radius being not greater than the radius of curvature of said recessed portion, and annular magnet means below said disc having opposite poles spaced apart adjacent the lower side of the disc, the outside diameter of said magnet means substantially exceeding the diameter of said sphere.

5. A tensioning device for yarn or other flexible strand material, comprising a disc of nonmagnetic material having axial bore therein for free passage of a strand to be tensioned, a sphere of magnetic material normally lying on the upper surface of said disc and over said bore to tension such strand, said sphere being upwardly unconfined and rollable laterally on said surface to provide any needed clearance for strand movement between itself and said bore, its diameter being substantially less than the diameter of said disc and substantially greater than the diameter of said bore, and annular magnet means below said disc having opposite poles spaced apart adjacent the lower side of the disc, the outside diameter of said magnet means substantially exceeding the diameter of said sphere.

6. A tensioning device for yarn or other fiexible strand material, comprising a disc of nonmagnetic material having an axial bore therein for free passage of a strand to be tensioned, a sphere of magnetic material normally lying on the upper surface of said disc and over said bore to tension such strand, said sphere being upwardly unconfined and rollable laterally on said surface to provide any needed clearance for strand movement between itself and said bore, its diameter being substantially less than the diameter of said disc and susbtantially greater than the diameter of said bore, magnet means below said disc exerting through the disc a magnetic flux drawing the sphere to said surface with a predetermined force and urging it from positions of lateral displacement on said surface to a centralized position over said bore, and a fixed rim surrounding said disc and presenting a free circular edge over which the strand is drawn toward said bore, said free edge being at a level above said disc surface but substantially below the top of said sphere so that the sphere bears against the strand only at a limited part of its lower hemisphere.

'7. A tensioning device for yarn or other flexible strand material, comprising a disc of nonmagnetic material having an axial bore therein for free passage of a strand to be tensioned and an upper surface symmetrically surrounding said bore including a concave recessed portion at said bore and a substantially fiat outer portion around the recessed portion, a sphere of magnetic material lying on said recessed portion and over said bore to tension such strand, the sphere being upwardly unconfined and rollable laterally on said surface to give any needed clearance for strand movement between itself and said bore, its radius being not greater than the radius of curvature of said recessed portion, annular magnet means below said disc having opposite poles spaced apart adjacent the lower side of the disc, the outside diameter of said magnet means substantially exceeding the diameter of said sphere, and. a fixed rim surrounding said disc and presenting a free circular edge over which the strand is drawn toward said bore, said free edge being at a level above said disc surface but substantially below the top of said sphere so that the sphere bears against the strand only at a limited part of its lower hemisphere.

HENRY C. UHLIG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,048,889 Ryden Dec. 31, 1912 1,436,942 Cabral Nov. 28, 1922 2,281,204 Raymond Apr. 28, 1942 2,373,513 Stevenson Apr. 10, 1945 2,478,926 Kingsbury Aug. 16, 1949 FOREIGN PATENTS Number Country Date 6,576 Great Britain Mar. 16, 1910 18,075 Great Britain Aug. 5, 1909 570,346 Germany Feb. 15, 1933 

